...except, really, when people use this argument, they're often not using that one data point in isolation. This is just one data point, true, but it's one _more_ data point on top of an increasingly long list of "freak" weather events.

500-year floods, 100-year storms, 100-year heat waves, etc. are becoming almost annual / decennial events. We absolutely should be willing to change our prior probability that global warming is A Real Thing from "very high" to "very, very high" for one more data point; that's how Bayesian inference works.

>500-year floods, 100-year storms, 100-year heat waves, etc. are becoming almost annual / decennial events.

Are you sure?

In the IPCC report, the authors have high confidence in more hot days and nights, but they are less sure about other forms of extreme weather increasing due to climate change. In fact, they mention that, globally, hurricane activity might decrease. Snowfall, forest fires seem to hanging steady.

500-year floods happening twice in a lifespan, or the same with 100-year storms or heat waves doesn't actually prove or disprove anthropocentric climate change either.

It's entirely plausible that it's related, but the fact that these things are happening more often in a 5 or 10 year period is not sufficient evidence alone.

Your comment reads like a hammer looking for a nail, like freak weather is obviously a natural consequence of rising global temperatures. I'm not sure that it is.

You should probably examine your assumptions a little bit more closely, and look for a testable link rather than a confirmation of an existing belief.

Unfortunately we don't have a control Earth to use.

They don't prove anything, but they are evidence in the baysiaan sense of the word. You should be (substantially) more surprised to see freak weather events if climate change isn't real than if climate change is.

Given your take, what kind of evidence would you envision seeing that would give you certainty that anthro cc is going on? Would the evidence arrive before it was too late to do anything?

Perhaps I wasn't clear: I believe that anthropocentric climate change is real.

I just don't have anything to suggest that all this recent freak weather is related to it. It's entirely possible that it is! It's also entirely possible that it isn't.

Freak weather is not, itself, some irrefutable proof of anthropocentric climate change. (We have plenty of that already.)

It could be that all the warming and sea ice loss that humans have caused (which no doubt has a bunch of cataclysmic stuff waiting in the wings for us, likely related to oceans and centered on plankton and other such planet-scale bio processes) is unrelated to the fact that we've had a bunch of bad weather lately, and that we've just been somewhat unlucky.

calculating expected extreme events isn't really that much different in principle than testing if a die is fair. if it's slightly loaded, you'll likely not notice for quite some time and might never be sure.

now the problem with climate change is that emissions now will yield indisputable evidence 20-30-50 years from now - a blink of an eye in climatology and likely point of no return for humanity.

note we do not lack evidence of global warming. https://www.theguardian.com/environment/2019/jul/22/memorial...

I encourage you to read my comment again, the second time more carefully.

Except when these "freak heat waves" start becoming common place.

In recent years many places around the would appear to be setting new temperature records on a rather regular basis.

Are they more common? Summers and winters don't feel any different to me than what they were when I was a child, they just get talked about a LOT more (my specific geographic location is probably a factor).

Take any region, country or city, look up heat highs or averages.

You will inadvertently find that around half a dozen extreme events happened in the last two decades.

Since a giant political movement seems to be based on the unwillingness to read more than ~24 characters at a time, here is a beautiful chart that really shows this: [0]. It does not even have text!

[0] https://en.wikipedia.org/wiki/Warming_stripes#/media/File:20...

This page lists the highest temperatures from around the world:

https://en.wikipedia.org/wiki/List_of_weather_records

The nice thing about that page is when you scroll down to the continent/country table data there is an option to sort by date column.

Sorting by date shows most of these records were set in the 21 century.

More worryingly many of those records were set in the last half decade.

While this might be coincidence, it could also be a trend and if it is the later then things are starting to look rather ominous. Time will tell.

This is false. USGCRP Climate Science Special Assessment: Volume 1: Chapter 6: Temperature Changes in the United States https://science2017.globalchange.gov/chapter/6/ Scroll down to figure 6.3. You can see that the 1920's to 1940's had more extreme heat events than any time since. Figure 6.4 is also useful to look at.

> my specific geographic location is probably a factor

A substantial one too, here's a very very rough map (which only measures one aspect, and has terrible resolution)

https://en.wikipedia.org/wiki/Regional_effects_of_climate_ch...

That's why we use the term "Climate Change". A freak heat wave and a freak blizzard both show that climate is changing, and not for the best.

Two sides of the same coin, we're fucking up our climate.

I think part of what makes people skeptical is that even if there was no anthropogenic CO2 in the atmosphere, there would still be these so-called "freak events". There were big hurricanes in the US's Revolutionary War era, for example, that had huge impacts on naval forces in the Caribbean. If climate change truly was a total hoax, believers could still point at a myriad of extreme weather events and say "look, climate change is real".

>A freak heat wave and a freak blizzard both show that climate is changing, and not for the best.

Freak events don't show anything, that's why they are freak events.

Yes, they do show things. When freak events happen over and over, year after year, that's a bad sign, and shows that things are changing.

One six on a dice is chance. Two sixes in a row are a fluke. Nine sixes are a loaded dice.

The trends are clear for anyone interested in discussing facts rather than ideology.

This is exactly the type of thinking that allows people to deny the reality of climate change. Dismissing "one data point", but doing it to all the thousands of data points. At some point, you have to look at all the data points and acknowledge that there is a distinct trend.

Here (20000km from Canada) on the radio climate specialist says "we don't know for sure if it's climate change at work, models don't agree".

My gut feeling is that if it is exceptionally high then model will hardly predict it.

Anyone here knows ?

The proximal cause of this heatwave is an omega block in the jet stream. Atmospheric models predict that these types of events should be less common as the world warms. At least that is what I was able to read about it a couple of days ago when I was worrying about this same question.

The problem is that for now, it's still a statistical anomaly, like the snow in Brazil is; it's uncommon, but if it's only a few days, it's going to be a blip on the radar and only a few tenths of a degree in annual statistics.

The temperature at the moment is weather; annual and multi-year statistics is climate.

Another commenter posted https://twitter.com/RARohde/status/1410157638109872134?s=19, which shows this is a statistical anomaly; only when this kind of weather happens year on year, and when the averages go up, can you speak of climate change.

(disclaimer: just being devil's advocate, climate change is real and "freak weather events" are becoming so common now that you can't deny it being a trend and the direct effect of global climate change)